This application claims the priority of German application 101 05 891.8, filed Feb. 9, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method of muffling the nose of successive components, by which an intermediate layer is placed between the two components, which are spaced away from one another at least in regions, and by which method the sound transmission and/or vibration transmission from one component into the other is reduced. The invention also relates to a noise absorber for successive components, which intermediate layer is arranged between the two components spaced away from one another at least in regions preferred embodiments are for use in the motor vehicle.
In particular, it is known from the automobile industry to arrange noise absorbers for muffling nose on covering parts of vehicles, such as the dashboard, the door coverings, the wheel house coverings, the fuel tank, etc. Conventional sound absorbers exist mainly in the form of fiber nonwovens and/or foam sheets and/or shaped foamed parts. Although these are lights and reasonable in price, they can be used only to a limited extent because of installation space problems. Although shape foamed parts largely reduce the space problems, their manufacturing requires high expenditures and their mounting is correspondingly expensive and difficult.
In addition, plate absorbers are known as noise absorbers. These are molded plastic plates with a high internal damping, or foils whose cavities act as absorbers. Systems of this type can also only be used to a limited extent, among other things, because of the above-mentioned installation space problems.
On the whole, all these noise absorbers have in common that they increase the total weight of a vehicle and thus also significantly raise its fuel consumption.
For the noise reduction, it is also known to feed foam particularly into inaccessible and/or small cavities. However, in addition to increasing the mass, the method also results in problems with respect to the later disposal.
It is an object of the invention to develop a method as well as a noise absorber for successive components which can be used in a simple manner also in a limited installation space and which is still as light and cost-effective as possible.
This object is achieved by a method of muffling the noise of successive components, by which an intermediate layer is placed between the two components, which are spaced away from one another at least in regions, and by which method as a result of the intermediate layer, the sound transmission and/or vibration transmission from one component to the other is reduced, characterized in that an air cushion is inserted as an intermediate layer, and in that the air cushion is placed at least indirectly on at least one surface respectively of each of the components. As a result of the construction of the noise absorber as a cost-effective and light air cushion, the latter, which is preferably not filled or only slightly filled, can be inserted in a simple manner in the respective spaces between the components. This can take place during the mounting of the components but also afterwards. The acoustic effect of the air cushion can be adjusted by way of its internal volume and/or its internal pressure. Furthermore, during the disposal of the components, the air cushion can be removed again in a simple manner, whereby a separation of types of a purity of types for recycling can advantageously be implemented.
Components are not only covering plates of any material or the like but also all possible aggregates. Likewise, this includes leadthroughs of a first component (such as a steering spindle) through another component (such as a front wall) which, as known, act as a sound bridge or may act as a sound bridge.
In a special manner, the air cushion is filled with air only after the connection or the finished installation of the components with one another, whereby the preferably elastic cover of the air cushion expands and a contact of the air cushion on the two components is achieved which is as good as possible.
Advantageously, a correspondingly preshaped air cushion, when its interior is filled, can even penetrate into undercuts and/or breakthroughs and/or, particularly in the case of leadthroughs, also into those clearances which occur between the receiving component and the component which is guided through.
The gas, preferably normal air, required for the inflating can be supplied to the air cushion by a blower, preferably a fan blower of the heater and/or of the air conditioner. In order to prevent an excessive filling, it is expedient to provide a relief valve and/or other outflow openings.
As a result of a thereby permitted targeted admission of pressure to the air cushion, the internal pressure and therefore also the acoustic absorption coefficient of this system can be regulated and optimized in a controlled manner as a function of the frequency of the noise to be muffled.
In the case of a outflow openings, it is useful, in turn to fludically connect these openings with the vehicle occupant compartment because, the temperature of the latter can then simultaneously be moderated thereby and/or the vehicle occupant compartment can even be air-conditioned. This is particularly useful when air cushions are used for muffling noise in the door area.
Additional useful further developments of the invention are described herein and in the claims. Furthermore, the invention will be explained in detail by means of the embodiment illustrated in the single figure.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.